DISCRETE ELEMENT MODELLING OF PARTICLE DEGARDATION OF RAILWAY BALLAST MATERIAL WITH PFC3D SOFTWARE

Abstract

Purpose. It is a very important issue to be able to determine the accurate particle degradation of railway ballast material. There are three different – but connecting – methodology for that: 1) full scale field tests, 2) full scale or reduced scale laboratory tests, 3) computer modelling, mainly with discrete element method (DEM). Options no. 1 and no. 2 need a lot of time and money, but for option no. 3 sophisticated software is needed that can consider the accurate micromechanical characteristics of ballast bed material. Methodology. In this paper the authors summarize their results related to modelling, having applied a software that uses DEM for calculation, as well as laboratory tests, namely uniaxial compression tests with reduced scale and computer tomography. Findings. The authors obtained the results that the uniaxial compression test in laboratory was able to be modelled by DEM software with an initial precision but in the future should be specified. The results are certified by measurements performed by computer tomography method. Originality. It is a very complicated issue to model the particle breakage of railway ballast not only particle movements in DEM software. There are many available software packages at the ‘market’, e.g. PFC, EDEM, YADE. Some of them are quite expensive, the others can be controlled by significantly difficult manner (special programming technique is needed, command line, etc.) The authors applied not only laboratory loading tests, but sophisticated computer tomography for their research. Practical value The results can be useful for railway engineering area. This article is a part of a PhD research at Szechenyi Istvan University, the PhD student is Erika Juhász. Her aim is to develop a method to be able to determine the more accurate ballast breakage, as well as develop assessment methodology related to special measurement techniques (e.g. GOM techniques, computer tomography, etc.). The publishing of this paper was supported by ÚNKP–19-3–I–SZE–13 project.